Heat exchanger



Oct. 20, 1936. A F, LEBRE HEAT EXCHANGER F'l d M I 5, 1954 1 11/9]. 1 e

2 Sheets-Sheet 1.

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7ALBERT FRANCOIS L BYv @W W ATTORNEY 2 Shets-Sheet 2 A. F. LEBRE HEATEXCHANGER Filed May 5, 1954 Oct. 20, 193

ATTOR Y Y ALBERT Fn/wgols EBRF; BY

Patented a, '20, 1936 PATENT OFFICE;

HEAT EXGHANGER Albert Francois Lebre, laria France Application May 5,1934, Serial No. 724,045

In France May 20, 1933 15 Claims. (01. 257-245) This invention relatesto plate heat-exchangers forfluids. I V i In apparatus-for the exchangeof heat between two fluidsit is desirable-to obtain a conl tact areawhich will be as'aiar'ge as'possible per unit volume, or per unit weightof metal,

To this end, in one type of apparatus each of the two fluid currentshavebeen divided into a large number of partial currents circulating inj tubes or between" plates or partitions. In another type of apparatus,the plates or surfaces separatingthe fluids have been; associated withadditional surfaces entirely immersed in oneof the fluids. Theseadditional surfaces, usually'in the form of fins or gills, are designedto transmit heat by conduction.

The apparatus of the latter type have advantages," as regardsconvenience of construction, owing to the fact that thejadditional sur-00 faces are not required to separate the two fluids and consequently,they are not required to fulfil the conditions of fluid-tightness andmechanical strength which are imposed on separating surfaces." Suchapparatus, of which a gilled tube is a well known example, areparticularly adaptedfor heat-exchange between fluids hav- .ing. verydifferent'heat-transfer coefficients, as

for example" water and air, whereas'apparatus of the first mentionedtype, are generally more suitable for'use with fluids havingheat-transfer coefiicients of the same order.

The advantages of both types of apparatus may be combined ,when themetal plates are extended across the two fluid currents at differenttemperatures, and the arrangement is such that the metal plates do notact as partitions between the fluid currents. but as fins or gills onboth sides of members which-form separating partitions between suchcurrents. It has already been 40 proposed to use as separating membersnarrow plates or bars inserted and pressed between successive plates inalternate relationship therewith, but with this arrangement it isdiflicult to obtain fluid-tight Joints between the contacting faces ofthe separating members and of the metal plates.-

The objects of my. present-invention are to make it possible to obtain amore satisfactory fluid-tightness and at the same time to increase 59the mechanical strength and rigidity of the apparatus.

With these objects in view, the heat-exchanger according to my inventioncomprises a plurality of adjacent or piled up parallel plates extending55 on both sides of partitions which, separate the fluid currents atdifierent temperatures, and it is characterized in that said partitionsare formed offolded parts either distinct from or integral with theparallel plates, said foldedparts hav ,ing at the juncture between saidpartitions and plates an interlocking engagement with each other orwith'said plates whereby the piled up plates are correctly spaced andform a rigid whole. 1

In the preferred embodiment of my invention, one ormore partitionsare.formed of a continuous plate folded zigzag fashion and alternatelyenclosing in its successive folds the edges ofladjacent piles of platesor gills on both sides thereof. With this arrangement the plates areinterrupted where they meet the partition and com-- pletefluid-tightness between the conduits on both sides of the partition isobtained without soldering or welding. v

In other constructions the platesare continuous and the partitions areformed of folded portions of the plates themselves'or of other partsengaged by folded portions 6f the plates.

In all these constructions the piled metal plates formingthe gills arenot used to separate the difierent fluids in which they are immersed.

, They mayaccordingly be as thin and as close together as is desired, sothat a very large contact area per unit volume, or per unit weight ofmetal may be obtained even if the fluids are at different pressures, orhave different chemical compositions, since such fluids arecompletelyseparated by the partitions braced by said plates. This renders theapparatus particularly suitable for performing heat-exchange with verysmall temperature differences, tov recuperate waste heat for examplefrom combustion gases, to carry out the cooling of compressed gases instage compression and generally to perform heat.

exchanges with gases considered unsuitable on account of the smallheat-transfer coefllcient from the gases to a metal.

In the accompanying drawings which illustrate by way of example,variouslconstructional 'forms of my invention:

' Fig. 1 is a cross-section, on line 1-1 of Fig. 2, showing a heatexchanger according to my in-, vention, the section being at rightangles to the direction of flow of the fluids-at different temperatures.

Fig. 2 is a side elevation viewed from line 11-11 of Fig. l, and

' Figs. 3 and 4 are part sections on and IV-IV respectively of Fig. 2. V

Flgs'. 5 and 6 illustrate on a larger scale a line mnr manner ofengaging with each other the end of the plates or gills and the folds inthe partition, before and after the pile is pressed.

Figs. 7 and 8 are views similar to the two preceding figures and show amodification.

Figs. 9 and 10 likewise show another modification.

Fig. 11 is a cross-sectional view and Fig. 12 a top view showing afurther constructional form, Fig. 13 being a modification of the formshown in Fig. 11.

Figs. 14, 15 and 16 are cross-sectional views showing still furtherconstructional forms with different manners of forming partitions withinthe piled plates.

In the example illustrated in Figs. 1 to 4, the piled up plates forminner gills I and outer gills I the adjacent edges of which are engagedin alternate folds of a sheet metal plate 'I folded zigzag fashion. Theplates are surrounded by a casing [the two parts of which are clampedtogether by means of bolts 3.

The plate 1 forms a continuous partition en-' closing on both sides acentral conduit 5 and separating it from two side conduits 6. The fluidsto be subjected to heat-exchange are circulated, one in conduit 5, theother in the two conduits 6.

The arrangement shown lends itself to the parallel and symmetricalcirculation of the two fluids, with a methodical or a counter currentheatexchange, the gills I, I' conducting heat in a direction at rightangles to the direction of flow of the fluids. Thus, for example, theheat collected by the central gills will separate into two currents ofopposite directions, flowing towards both ends, across the respectivepartitions.

When the fluids have the same heat-transfer coeidcient, and have toundergo temperature variations of the same order while they flow throughthe heat-exchanger, I use the same number of gills I and I' and makethem of the same size whereas if the said coemcients and the temperaturevariations are not the same, the length of the gills or their number maybe proportioned to the amount of heat to be transferred to the metal persurface unit by each fluid. This makes it possible to extend the use ofmy improved heat exchanger to the treatment of fluids of widelydifferent natures, as a gas and a liquid.

The inner conduit 5 being braced by the gills extending therethrough,can receive gases at high or low pressures, the gills or platescooperating with the partitions in order not only to transmit the heat,but also to afford the necessary me-.

chanical strength to ensure the separation of gaseous fluids even whensaid fluids are at very different pressures.

The plate I being continuous, affords complete fluid-tightness betweenthe conduits 5 and 6. Although the gills are not continuous, it ispossible to obtain by suitable pressure, such a good contact between theends of the gills and the folds of the plate I, as to cause the heattransfer to take place in a manner just as satisfactory as if the gillswere continuous. Instead of a single plate I forming both partitions asshown, each partition may of course be formed of a separate folded platecorresponding to the folded end portions of the plate I unconnected toone of the parallel plates.

Similar folded plates can also be used to close the lateral conduits 6on their outer sides, if desired.

Fig's 5 and 6 respectively show, before and after pressure is applied,how a good contact can be secured, the plate I being bent around thefolded edges 8, 8 of the gills I, I. In the example of Figs. 7 and 8,the plate I is bent about the inturned edges of the gills I, I, while inthe slightly modified form illustrated in Figs. 9 and 10, the edges ofthe gills I, I are turned around wires or rods 9.

In order to ensure a. good contact with the partitions I when the platesI, I' forming the gills are folded, turned or bent at their edges, it isof advantage to make such plates of coldworked metal and to make thezigzag partitions of hard metal so that after the parts have beenpressed together, the resiliency of the metal cooperates in maintaininga good contact.

Figs. 11 and 12, illustrate an arrangement which provides a hookingengagement between the plates I and rods or wires 9 which, whensuperposed, form the separating partitions. At the places where thepartitions are to be formed, the plates are folded or creased likecertain hinge elements which comprise sections alternately curvedupwards and downwards, the wires or rods, numbering two or more to eachplate, passing through the creases like the pins of a hinge. the creasesof adjacent plates mutually fitting within one another. In Fig. 11 thecreases enfold two and in Fig. 13 three wires or rods.

In Fig. 14 is illustrated an arrangement which preserves the continuityof the gills, the plates I,

I having creases with a double curvature l0 adapted to flt within eachother so as to form the separating partitions.

In another modification (Fig. 15) the plates II, I2, I3 forming thegills are themselves bent zigzag fashion and fltted so that they form,two by two, by the superposition of their folds in alternating relation,the partitions necessary for separating the conduits 5 and 6.

I may also use corrugated plates for forming the gills. Fig. 16 shows anarrangement in which corrugated metal sheets I4 are combined with rodsor wires I5 which, by their superposition, form the lateral partitions.It will of 'course be understood that the use of corrugated plates maybe combined with any of the methods of forming the separating partitionsabove referred to by way of example.

The heat exchange elements constructed in accordance with my inventionmay be made of any suitable metal, for example aluminium, which metalcombines with a light weight the advantage of a good thermal conduction,or copper which is suitable for welding or soldering, or iron which ischeap and suitable for galvanizetion.

When such heat exchange elements are enclosed in an outer casing, it maybe advantageous to arrange such casing as shown in Figs. 1 to 4 so thatthe piled up plates are pressed together while being able to expandfreely, independently of the casing. To both ends of the casing I mayconnect headers as shown in Figs. 2 to 4, comprising a central conduitI6 and two sides conduits I'I decreasing in cross-section, so as toensure a uniform flow of fluid towards and from the piled plates.

Other modifications may of course be made within the scope of myinvention as defined by the following claims:

I claim:

1. In a heat-exchange apparatus for fluids, the combination of piled upparallel plates with partitions extending transversely of said plates,said partitions being formed of folded parts having --an interlockingengagement with said plates,

partitions being formed of folded parts distinct from and having aninterlocking engagement withsaid plates, said partitions being adaptedto separate fluid currents at different temperatures, said-platesextending in the manner of gills on both sides of said partitions.

' 3. In a heat-exchange apparatus for fluids, the combination of piledup parallel plateswith partitions extending transversely of said.plates, said partitions being formed of folded parts integral with atleast one of said plates and having an interlocking engagement with theother of said plates, said partitions being adapted to separate fluidcurrents at different temperatures, said plates extending in the mannerof gills on both I sides of said partitions.

4. In a heat-exchange apparatus for fluids, the combination, in asurrounding casing, of fluidtight partitions dividing said casing intothree parallel passages, adjacent plates extending in the manner ofgills on both sides of said partitions and across said passages, saidpartitions being formed of folded parts having interlocking engagementwith the edges of said plates.

5. In a heat-exchange apparatus for fluids,the combination of two pilesof parallel plates with a transverse partition therebetween adapted toseparate two gas currents at different temperatures, said partitioncomprising a sheet folded zigzagfashion and alternately enclosing in itsfolds the edges of plates on both side thereof. 1.

6. In a heat-exchange-apparatus for fluids, the combination, in asurrounding casing, of three adjacent piles of parallel plates with twotransverse partitions, each of said partitions comprising a sheetfoldedzigzag-fashion and alternately enclosing in its folds the edges ofplates of two of saidadjacent piles. I

'7. In a heat-exchange apparatus for fluids the combination of a thinmetal plate folded zigzagfashion, a series of parallel flat plates oneach side of said folded plate, said folded plate alternately clampingin its folds the edges of the flat plates on either side thereof. saidflat plates thus being spaced from each other and forming a rigid unitwith said folded plate,'a casing surrounding said unit, said casingbeing open at both ends, said folded plate forming a fluid-tightlongitudinal partition within. l

8. In a heat-exchange apparatus, the combination of piled up parallelplates with partitions extending transversely of said plates, saidpartitions having an interlocking engagement with said plates, saidpartitions being adapted to separate fluid currents at differenttemperatures,

said plates extending in the manner of gills on both sides of saidpartitions.

9. In a heat exchange apparatus for fluid, the combination of aplurality of plates and partitions extending transversely of the plates,said partitions being formed of folded parts for holding said plates inspaced relation and to separate 'fluidcurrents at differenttemperatures.

10.'In a heat exchange apparatus for fluid, the combination of aplurality of plates and partitions extending transversely of saidplates, said partitions being formed of folded parts adapted to separatefluid currents at different temperatures, said plates extending in themanner of gills on both sides of said partitions.

11. In a heat exchange apparatus for fluid, the combination of aplurality of plates and partitions extending transversely of saidplates, .said partitions being formed of folded parts distinct from andhaving an interlocking engagement with said plates, said partitionsbeing adapted to separate fluid currents at different temperatures.

12. In a heat exchange apparatus for fluid, the combination of aplurality of plates and partitions extending transversely of saidplates, said partitions beingformed of folded parts integral with one ofsaid plates and having an interlocking engagement with the other of saidplates, said partitions being adapted to separate fluid currents atdifferent temperatures.

13. In a heat exchange apparatus for fluid, the

combination in a surrounding casing, of adjacent piles of platesseparated by transverse partitions, each of said partitions comprising asheet folded zigzag fashion and alternately incloslng in its folds theedges of plates of two of said'adjacent piles.

' 1,4. In a heat exchange apparatus for fluid, the combination in asurrounding casing, of adjacent piles of plates terminating in enlargededgeportions separated by transverse partitions, each of said partitionscomprising a'- sheet folded zigzag fashion and alternately enclosing inits folds the edges of plates of two of said adjacent piles;

15-. In a heat exchange apparatus for fluid, the combination in asurrounding casing, of adjacent piles of plates the adjacent edges ofwhich terminate in folds separated by transverse partitions, each ofsaid partitions-comprising a sheet folded zigzag fashion and alternatelyenclosing in its folds the folded edges of plates of two of saidadjacent piles.

